GRIS Coordinates: Solar Rotation

When using the updated GRIS data, Morten and Adur were not 100 percent sure whether the coordinates specified in the WCS keywords for the slit kws were correct. Definitely check this and write down some evidence.

Also check:

• Blue and Red observations
• Multimap observations
• Sit and Stare
• Polarimetric observations

Steps:

1. Collect testing data
2. Implement plotting of the coverage over a concurrent HMI Image
3. Compare with image content
4. Document results somewhere, eg here on gitlab